AWR1642: How to use LP8752 control the reset of AWR1642

Adam Yao94020

Part Number: AWR1642

Hi,
In TI's Autonomous Mode radar system topology, we can see the NErrorOut and NREST of AWR1642 are connected to LP8752 (see below figure). Does it mean AWR1642 can send error signal to LP8752 when exception happens and then use LP8752 to fully reset itself? If yes, which pins in LP8752 can serve this application?

Thanks,
Adam

over 8 years ago

0 Vivek Dham over 8 years ago

TI__Guru 58035 points

Hello Adam,
This is a generic block diagram and not specific to LP87524 PMIC.
The nRST signal to the AWR1642 can be pulled high to the 3.3V supply from the PMIC, just as its done in the TI EVM design. The LP8752 part specifically cannot use the nERROR signal directly , but if the user has a PMIC that can use the nerror signal he can connect it to the PMIC.
The user can also send a message over CAN to the central unit incase of nerror.

Regards,
Vivek

0 Adam Yao94020 over 8 years ago in reply to Vivek Dham

TI__Genius 10910 points

Hello Dham,
Does that mean in AWR1642 signle chip radar solution we have no way to NREST the device with LP87524? I am afraid there is still some parts not reset by warm reset (Debug SS, FUSEFRAM&Test controller in figure3-2 of TRM). Will it cause any problem in the next system running after warm reset if an error happened in AWR1642?

Thanks,
Adam

0 Adam Yao94020 over 8 years ago in reply to Adam Yao94020

TI__Genius 10910 points

Hello Dham,
Another question from customer about the figure is why we use IGN and 5v together to control the PMIC? Their concern is that there could cause some static power dispersing from the 5V when it connect to PMIC but IGN not triggered. Another solution is to use any 5V supply to control the PMIC. What is your consideration of the system?

Thanks,
Adam

0 Vivek Dham over 8 years ago in reply to Adam Yao94020

TI__Guru 58035 points

Hello Adam,
The IGN signal is only representing that the PMIC could be disabled when the IGN is OFF to save power. If only 5V supply is used to enable the PMIC then even without the ignition being ON the PMIC could be enabled because the 12 V car battery would always be present.

Regards,
Vivek

0 Adam Yao94020 over 8 years ago in reply to Vivek Dham

TI__Genius 10910 points

Hello Vivek,
Do you know what is the typical use case in car for radar power supply, using 5V supply + IGN or only 5V controlling all?

Thanks,
Adam

0 Vivek Dham over 8 years ago in reply to Adam Yao94020

TI__Guru 58035 points

Hello Adam,
This would be very customer or user specific implementation. But I would assume everybody would have some form of gating with IGN to make sure the PMIC is not enabled when the vehicle is OFF.

Regards,
Vivek

0 Adam Yao94020 over 8 years ago in reply to Vivek Dham

TI__Genius 10910 points

Hello Vivek,
Thanks for your reply, I am clear now. Could you also help to check my previous post in

----------------------------

Does that mean in AWR1642 signle chip radar solution we have no way to NREST the device with LP87524? I am afraid there is still some parts not reset by warm reset (Debug SS, FUSEFRAM&Test controller in figure3-2 of TRM). Will it cause any problem in the next system running after warm reset if an error happened in AWR1642?

_________________

Thanks,
Adam

0 Vivek Dham over 8 years ago in reply to Adam Yao94020

TI__Guru 58035 points

Hello Adam,
There are external supervisor and reset circuits that can be used to reset the 1642 device when nERROR signal goes low. TI does have a wide range of such products, you can refer to this page www.ti.com/.../supervisor-reset-ic-products.page for details.

Regards,
Vivek

0 Vivek Dham over 8 years ago in reply to Vivek Dham

TI__Guru 58035 points

Hello Adam,
Dis this clarify your query?

Regards,
Vivek

0 Adam Yao94020 over 8 years ago in reply to Vivek Dham

TI__Genius 10910 points

Hello Vivek,
Yes, I am clear now. Thanks for your reply.

Regards,
Adam

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AWR1642: How to use LP8752 control the reset of AWR1642